What age do toddler dress and undress themselves?

I think if you haven't been exposing your kid to this because thus far you've always been doing this for the child, then no worries - but if you've been encouraging and they still aren't able simple things like pulling their pants down, then there may be concern. I'd encourage them to do some of the more simple tasks which you can also prepare - like putting on socks - I used to scrunch up the sock a bit so it was easy for them to put in. That said I had one kid who was early and one kid who was late-ish and both of them are fine in the long run.